1. Field of the Invention
The present invention generally relates to an image blurring technique for rendering an image indistinct, and more particularly, to a method and apparatus for giving a blurring effect of various levels to a given image.
2. Description of the Related Art
With the growth of technology, a variety of electronic devices, such as a smart phone or a tablet PC, having a camera module have become increasingly popular. Also, an edit application or program for giving various graphical effects to an image captured by a camera module has become widely used.
One of such graphical effects is blurring which intentionally degrades the quality (or definition) of a given image so that a user may accept the image as indistinct. Typically, blurring is processed by applying a mean filter or a Gaussian filter to an image. In this case, the filter is applied to a lot of pixels contained in a single image. Therefore, as the number of pixels contained in the image increases, a computation complexity for blurring is also increased.
Typical blurring determines the value of an image pixel as the average of neighboring N-by-N pixel data with the same weighted values applied. Specifically, for quick blurring, a sum image is generated first and then blurring is computed using the generated sum image. Since the same weighted values are applied to neighboring N-by-N pixel data, box-shaped boundaries may often appear in a blur image. This undesirable phenomenon may be more serious when the value of N is higher. In addition, a processed image may appear as an overlap of an original image rather than a blur image.